Portable electronic devices, such as e-book readers or tablet computers, have become increasingly popular recently. One constraint on usability for portable electronic devices is their limited battery life, which requires that users recharge the device frequently after some period of usage. For e-book readers in particular, such as those with electronic paper displays (EPDs), it is desirable to provide extended battery life. Many users of e-book readers expect to go many days, weeks, or months on a single charge. However, reduced weight is also a highly desirable feature for portable electronic devices, particularly e-book readers which in typical usage may be held by the user for hours at a time. As a result, increasing the size of the battery to improve battery life has the undesirable effect of increasing the weight of the device. Accordingly, there is a need for improved electronic devices which can provide strong battery life while minimizing overall device weight.